Technical product documentation - General principles of representation - Part 3: Views, sections and cuts (ISO 128-3:2020)

This document specifies the general principles for presenting views, sections and cuts applicable to
various kinds of technical drawings (e.g. mechanical, electrical, architectural, civil engineering),
following the orthographic projection methods specified in ISO 5456-2. Views and sections for
shipbuilding technical drawings are discussed in ISO 128-15. Views and sections for 3D models are
discussed in ISO 16792.
Attention has also been given in this document to the requirements of reproduction, including
microcopying in accordance with ISO 6428.

Technische Produktdokumentation (TPD) - Allgemeine Grundlagen der Darstellung - Teil 3: Ansichten, Schnitte und Schnittansichten (ISO 128-3:2020)

Dieses Dokument legt die allgemeinen Grundlagen zur Darstellung von Ansichten, Schnittansichten und Schnitten dar, die für verschiedene Arten von technischen Zeichnungen gelten (z.Mechanik, Elektrik, Architektur, Tiefbau), wobei die in ISO 5456 2 dargelegten orthogonalen Projektionsmethoden befolgt werden. Ansichten und Schnitte in Schiffbauzeichnungen sind Gegenstand von ISO 128 15. Ansichten und Schnitte in 3D Modellen sind Gegenstand von ISO 16792.
Die Anforderungen an die Vervielfältigung, einschließlich Mikroverfilmung nach ISO 6428, wurden in diesem Dokument ebenfalls berücksichtigt.

Documentation technique de produits (TPD) - Principes généraux de représentation - Partie 3: Vues, sections et coupes (ISO 128-3:2020)

Le présent document établit les principes généraux de représentation des vues, des sections et des coupes applicables aux différents types de dessins techniques (par exemple génie mécanique, génie électrique, génie architectural, génie civil) suivant les méthodes de projection orthographique, spécifiées dans l'ISO 5456‑2. Les vues et sections pour les dessins techniques de construction navale sont discutées dans l'ISO 128‑15. Les vues et sections pour les modèles 3D sont discutées dans l'ISO 16792.
Les spécifications du présent document ont été établies en tenant compte des exigences de reproduction, y compris celles de la micrographie, conformément à l'ISO 6428.

Tehnična dokumentacija izdelkov - Splošna načela prikazovanja - 3. del: Pogledi, prerezi in odrezi (ISO 128-3:2020)

General Information

Status
Published
Public Enquiry End Date
03-Nov-2019
Publication Date
07-Sep-2020
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
03-Aug-2020
Due Date
08-Oct-2020
Completion Date
08-Sep-2020

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SLOVENSKI STANDARD
SIST EN ISO 128-3:2020
01-oktober-2020
Tehnična dokumentacija izdelkov - Splošna načela prikazovanja - 3. del: Pogledi,
prerezi in odrezi (ISO 128-3:2020)

Technical product documentation - General principles of representation - Part 3: Views,

sections and cuts (ISO 128-3:2020)

Technische Produktdokumentation (TPD) - Allgemeine Grundlagen der Darstellung - Teil

3: Ansichten, Schnitte und Schnittansichten (ISO 128-3:2020)

Documentation technique de produits (TPD) - Principes généraux de représentation -

Partie 3: Vues, sections et coupes (ISO 128-3:2020)
Ta slovenski standard je istoveten z: EN ISO 128-3:2020
ICS:
01.110 Tehnična dokumentacija za Technical product
izdelke documentation
SIST EN ISO 128-3:2020 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 128-3:2020
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SIST EN ISO 128-3:2020
EN ISO 128-3
EUROPEAN STANDARD
NORME EUROPÉENNE
July 2020
EUROPÄISCHE NORM
ICS 01.100.01
English Version
Technical product documentation - General principles of
representation - Part 3: Views, sections and cuts (ISO 128-
3:2020)

Documentation technique de produits (TPD) - Technische Produktdokumentation (TPD) - Allgemeine

Principes généraux de représentation - Partie 3: Vues, Grundlagen der Darstellung - Teil 3: Ansichten,

sections et coupes (ISO 128-3:2020) Schnitte und Schnittansichten (ISO 128-3:2020)

This European Standard was approved by CEN on 12 June 2020.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this

European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references

concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN

member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by

translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management

Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 128-3:2020 E

worldwide for CEN national Members.
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SIST EN ISO 128-3:2020
EN ISO 128-3:2020 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 128-3:2020
EN ISO 128-3:2020 (E)
European foreword

This document (EN ISO 128-3:2020) has been prepared by Technical Committee ISO/TC 10 "Technical

product documentation" in collaboration with Technical Committee CEN/SS F01 “Technical drawings”

the secretariat of which is held by CCMC.

This European Standard shall be given the status of a national standard, either by publication of an

identical text or by endorsement, at the latest by January 2021, and conflicting national standards shall

be withdrawn at the latest by January 2021.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

According to the CEN-CENELEC Internal Regulations, the national standards organizations of the

following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,

Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the

United Kingdom.
Endorsement notice

The text of ISO 128-3:2020 has been approved by CEN as EN ISO 128-3:2020 without any modification.

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SIST EN ISO 128-3:2020
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SIST EN ISO 128-3:2020
INTERNATIONAL ISO
STANDARD 128-3
First edition
2020-06
Technical product documentation
(TPD) — General principles of
representation —
Part 3:
Views, sections and cuts
Documentation technique de produits (TPD) — Principes généraux de
représentation —
Partie 3: Vues, sections et coupes
Reference number
ISO 128-3:2020(E)
ISO 2020
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SIST EN ISO 128-3:2020
ISO 128-3:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
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SIST EN ISO 128-3:2020
ISO 128-3:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Basic conventions for views ...................................................................................................................................................................... 2

4.1 General information on views.................................................................................................................................................... 2

4.2 Choice of views ....................................................................................................................................................................................... 3

4.3 Partial views .............................................................................................................................................................................................. 3

4.4 Simplified view of symmetrical parts ......... ......................................................................................................................... 4

4.5 First angle projection method ................................................................................................................................................... 4

4.6 First angle projection method views ................................................................................................................................... 4

4.7 First angle projection graphical symbol ............................................................................................................................ 5

4.8 Third angle projection method ................................................................................................................................................. 5

4.9 Third angle projection method views ................................................................................................................................. 5

4.10 Third angle projection graphical symbol ......................................................................................................................... 6

4.11 Other projection methods ............................................................................................................................................................. 6

4.12 Enlarged features .................................................................................................................................................................................. 6

5 Reference indication for views and enlarged features ................................................................................................. 7

5.1 General ........................................................................................................................................................................................................... 7

5.2 Details of the reference indication ......................................................................................................................................... 7

5.3 Examples of indication ..................................................................................................................................................................... 8

6 General information on cuts and sections ................................................................................................................................. 9

6.1 General ........................................................................................................................................................................................................... 9

6.2 Indication of cuts and sections .................................................................................................................................................. 9

6.2.1 Cutting plane ....................................................................................................................................................................... 9

6.2.2 Identification of the cutting plane..................................................................................................................... 9

6.2.3 Identification of the cuts and sections .......................................................................................................... 9

6.2.4 Reference indication for cuts and sections ............................................................................................10

6.3 Sections revolved in the relevant view ............................................................................................................................11

6.4 Cuts/sections of symmetrical parts ...................................................................................................................................12

6.5 Local cuts/sections ...........................................................................................................................................................................12

7 Basic conventions for representing areas on cuts and sections.......................................................................13

7.1 General information on cuts and sections ....................................................................................................................13

7.2 Hatching .....................................................................................................................................................................................................13

7.3 Shading or toning ...............................................................................................................................................................................14

7.4 Extra-wide continuous outlines ............................................................................................................................................15

7.5 Thin sections ..........................................................................................................................................................................................15

7.6 Thin adjacent sections ...................................................................................................................................................................15

7.7 Specific materials ...............................................................................................................................................................................16

Annex A (normative) Graphical symbols ......................................................................................................................................................17

Annex B (informative) Former practices .......................................................................................................................................................20

Annex C (normative) Views on mechanical engineering technical drawings .........................................................22

Annex D (normative) Sections on mechanical engineering technical drawings ..................................................34

Annex E (normative) Projection methods in building technical drawings ................................................................39

Annex F (normative) Representation of views, sections and cuts on construction drawings ...............41

Bibliography .............................................................................................................................................................................................................................48

© ISO 2020 – All rights reserved iii
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SIST EN ISO 128-3:2020
ISO 128-3:2020(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 10, Technical product documentation, in

collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/SS

F01, Technical drawings, in accordance with the Agreement on technical cooperation between ISO and

CEN (Vienna Agreement).
This first edition cancels and replaces the following documents:
— ISO 128-30:2001
— ISO 128-33:2018
— ISO 128-34:2001
— ISO 128-40:2001
— ISO 128-44:2001
— ISO 128-50:2001
The main changes to these documents are as follows:
— harmonization of the former parts listed above;
— introduction of reference indication for views and enlarged features;

— use of arc arrow in special position of views moved to a former practice annex.

A list of all parts in the ISO 128 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved
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SIST EN ISO 128-3:2020
ISO 128-3:2020(E)
Introduction

This document contains generally applicable rules for the presentation of views, sections and cuts in all

kinds of technical product documentation. The first angle projection method (formerly referred to as

method E) and the third angle projection method (formerly referred to as method A) are described in

more detail in ISO 5456-2.

All figures in this document, excluding Figure 1, Figure 6 and Figure 7, have been drawn in first-angle

projection method unless other methods are stated. It should be understood that third-angle projection

or other methods could have been used equally well without prejudice to the principles established.

The application of views, sections and cuts within drawings of special technical fields varies

considerably. Therefore, rules of application specific to technical fields are given in Annex A, B and C.

© ISO 2020 – All rights reserved v
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SIST EN ISO 128-3:2020
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SIST EN ISO 128-3:2020
INTERNATIONAL STANDARD ISO 128-3:2020(E)
Technical product documentation (TPD) — General
principles of representation —
Part 3:
Views, sections and cuts
1 Scope

This document specifies the general principles for presenting views, sections and cuts applicable to

various kinds of technical drawings (e.g. mechanical, electrical, architectural, civil engineering),

following the orthographic projection methods specified in ISO 5456-2. Views and sections for

shipbuilding technical drawings are discussed in ISO 128-15. Views and sections for 3D models are

discussed in ISO 16792.

Attention has also been given in this document to the requirements of reproduction, including

microcopying in accordance with ISO 6428.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 128-2:— , Technical drawings — General principles of presentation — Part 2: Basic conventions for lines

ISO 129-1, Technical product documentation (TPD) — Presentation of dimensions and tolerances — Part 1:

General principles

ISO 3098-1, Technical product documentation — Lettering — Part 1: General requirements

ISO 5456-2, Technical drawings — Projection methods — Part 2: Orthographic representations

ISO 6428, Technical drawings — Requirements for microcopying

ISO 10209:2012, Technical product documentation — Vocabulary — Terms relating to technical drawings,

product definition and related documentation

ISO 15519-1, Specification for diagrams for process industry — Part 1: General rules

ISO 81714-1, Design of graphical symbols for use in the technical documentation of products — Part 1:

Basic rules
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 10209 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
1) Under preparation. Stage at the time of publication: ISO/FDIS 128-2:2020.
© ISO 2020 – All rights reserved 1
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SIST EN ISO 128-3:2020
ISO 128-3:2020(E)
3.1
cut
sectional view
section (3.2) showing, in addition, outlines beyond the cutting plane

Note 1 to entry: While “cut” is generally used in the construction field, “section” is generally used in the

mechanical engineering field, regardless of the definitions in 3.1 or 3.2.
[SOURCE: ISO 10209:2012, 3.11, modified — Note 1 to entry added.]
3.2
section

representation showing only the outlines of an object lying in one or more cutting planes

Note 1 to entry: While “cut” is generally used in the construction field, “section” is generally used in the

mechanical engineering field, regardless of the definitions in 3.1 or 3.2.
[SOURCE: ISO 10209:2012, 3.61, modified — Note 1 to entry added.]
3.3
technical drawing

drawing showing a technical installation, process or product with a view to clarifying its structure and

enabling its construction

Note 1 to entry: For the purpose of this document, the term “technical drawing” is interpreted in the broadest

possible sense, encompassing the total package of documentation specifying the product (work piece,

subassembly, assembly).
[SOURCE: ISO 5127:2017, 3.4.7.54, modified — Note 1 to entry added.]
4 Basic conventions for views
4.1 General information on views

The most informative view of an object shall be used as the principle view, taking into consideration, for

example, its functioning position, position of manufacturing or mounting.

Each view, with the exception of the front or principal figure (view, plan, principal figure), shall be

given clear identification with a capital letter, repeated near the reference arrow needed to indicate the

direction of viewing for the relevant view. Whatever the direction of viewing, the capital letter shall

always be positioned in normal relation to the direction of reading and be indicated either above or on

the right side of the reference arrow.

The reference arrow is defined in Annex A (for the former practice of arc arrow, see Annex B), as is the

lettering height of the identification.

The designated views may be located irrespective of the principal figure. The capital letters identifying

the referenced views shall be placed immediately above the relevant views (see Figure 1).

2 © ISO 2020 – All rights reserved
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SIST EN ISO 128-3:2020
ISO 128-3:2020(E)
Figure 1 — Identification of referenced views

For applying views and sections to mechanical engineering technical drawings, Annex C and Annex D

shall apply. For applying projection methods in building technical drawings, Annex E shall apply. For

applying views, sections and cuts to construction technical drawings, Annex F shall apply.

4.2 Choice of views

When views (including cuts and sections) are needed, these shall be selected according to the following

principles:

— limit the number of views (and cuts and sections) to the minimum necessary but sufficient to fully

delineate the object without ambiguity;
— avoid the need for hidden outlines and edges;
— avoid unnecessary repetition of a detail.
Views and sections for 3D models are given in ISO 16792.
4.3 Partial views

Features needing specific illustration, but not meriting a full view, can be illustrated using a partial view

limited by a continuous narrow line with zigzags of type 01.1 according to ISO 128-2:— (see Figure 2).

© ISO 2020 – All rights reserved 3
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SIST EN ISO 128-3:2020
ISO 128-3:2020(E)
Figure 2 — Partial view
4.4 Simplified view of symmetrical parts

To save time and space, symmetrical objects can be drawn as a fraction of the whole [see Figure 3 a), b)

and c)].

The line of symmetry is identified at each of its ends by two narrow short parallel lines drawn at right

angles to it [see Figure 3 a), b) and c)]. The graphical symbol for symmetry shall be drawn in accordance

with A.3.
a) Example 1 b) Example 2 c) Example 3
Figure 3 — Examples of simplified views of symmetrical parts
4.5 First angle projection method

The first angle projection method, if used, shall be in accordance with ISO 5456-2.

4.6 First angle projection method views

With reference to the front view, (a), the other views are arranged as follows (see Figure 4):

— the view from above, (b), is placed underneath;
— the view from below, (e), is placed above;
— the view from the left, (c), is placed on the right;
4 © ISO 2020 – All rights reserved
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SIST EN ISO 128-3:2020
ISO 128-3:2020(E)
— the view from the right, (d), is placed on the left;

— the view from the rear, (f), may be placed on the left or right, as convenient.

Figure 4 — First angle projection method
4.7 First angle projection graphical symbol

The graphical symbol for the first angle projection method is shown in Figure 5. The proportions and

dimensions of this graphical symbol are specified in ISO 5456-2.
Figure 5 — First angle projection graphical symbol
4.8 Third angle projection method

The third angle projection method, if used, shall be in accordance with ISO 5456-2.

4.9 Third angle projection method views

With reference to the front view, (a), the other views are arranged as follows (see Figure 6):

— the view from above, (b), is placed above;
— the view from below, (e), is placed underneath;
— the view from the left, (c), is placed on the left;
— the view from the right, (d), is placed on the right;

— the view from the rear, (f), may be placed on the left or right, as convenient.

© ISO 2020 – All rights reserved 5
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SIST EN ISO 128-3:2020
ISO 128-3:2020(E)
Figure 6 — Third angle projection method
4.10 Third angle projection graphical symbol

The graphical symbol for the third angle projection method is shown in Figure 7. The proportions and

dimensions of this graphical symbol are specified in ISO 5456-2.
Figure 7 — Third angle projection graphical symbol
4.11 Other projection methods

Refer to ISO 5456-2 for information on other projection methods such as mirrored orthographic

projections.
4.12 Enlarged features

When the scale of a technical drawing does not allow all features to be clearly shown or dimensioned,

the unclear features shall be enclosed or encircled by a continuous narrow line (type 01.1), with the area

thus enclosed identified by a capital letter. The features in the area shall also be shown on an enlarged

scale, in a view that is broken with a continuous narrow freehand/free formed curve line (type 01.1).

This shall be accompanied by the identification letter and an indication of the scale beside it between

parentheses, as shown in Figure 8. The rules for lettering height are discussed in Annex A.

Figure 8 — Enlarged features
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SIST EN ISO 128-3:2020
ISO 128-3:2020(E)

For unambiguous relation between the circle and the identification letter, a leader line by a continuous

narrow line (type 01.1) and a reference line by a continuous narrow line (type 01.1) should be drawn.

See Figure 9.
Figure 9 — Enlarged features with leader line
5 Reference indication for views and enlarged features
5.1 General

On large-format mechanical technical drawings and technical drawings consisting of more than one

drawing sheet with an extensive amount of views and enlarged features, the readability should be

improved by information (reference indication) after the identification letter of the views.

The purpose is to find the views and the identification letters more easily on the technical drawing or

drawings.

On construction drawings, designations for views and enlarged features can be complemented by

general reference to other drawings containing the views/features.
5.2 Details of the reference indication

The reference indication after the identification letter on the views shall be in accordance with

ISO 15519-1.
Examples with explanation are shown in Figure 10 and Figure 11.
Figure 10 — Details of the reference indication with a single drawing
© ISO 2020 – All rights reserved 7
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SIST EN ISO 128-3:2020
ISO 128-3:2020(E)
Figure 11 — Details of the reference indication with multiple drawings
5.3 Examples of indication
Examples of indication are given in Table 1.
Table 1 — Examples of indication
Indication on technical dra
...

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